State Codes and Statutes

Statutes > California > Hsc > 18944.40-18944.41

HEALTH AND SAFETY CODE
SECTION 18944.40-18944.41



18944.40.  (a) Straw-bale walls, when covered with plaster, drywall,
or stucco, shall be deemed to have the equivalent fire resistive
rating as wood-frame construction with the same wall-finishing
system.
   (b) Minimum bale wall thickness shall be 13 inches.
   (c) Buildings with loadbearing bale walls shall not exceed one
story in height without substantiating calculations and design by a
civil engineer or architect licensed by the state, and the bale
portion of the loadbearing walls shall not exceed a height-to-width
ratio of 5.6:1 (for example, the maximum height for a wall that is 23
inches thick would be 10 feet 8 inches).
   (d) The ratio of unsupported wall length to thickness, for
loadbearing walls, shall not exceed 15.7:1 (for example, for a wall
that is 23 inches thick, the maximum unsupported length allowed is 30
feet).
   (e) The allowable vertical load (live and dead load) on top of
loadbearing bale walls plastered with cement or lime cement plaster
on both sides shall not exceed 800 pounds per linear foot, and the
resultant load shall act at the center of the wall. Straw-bale
structures shall be designed to withstand all vertical and horizontal
loads, and the resulting overturning and base shear, as specified in
the latest edition of the California Building Standards Code.
Straw-bale walls plastered with cement or lime cement plaster on both
sides shall be capable of resisting in-plane lateral forces from
wind or earthquake of 360 pounds per linear foot.
   (f) Foundations shall be designed in accordance with the
California Building Standards Code to accommodate the load created by
the bale wall plus superimposed live and dead loads. Supports for
bale walls shall extend to an elevation of at least six inches above
adjacent ground at all points, and at least one inch above floor
surfaces.
   (g) (1) Bale walls shall be anchored to supports to resist lateral
forces, as approved by the civil engineer or architect. This may be
accomplished with one-half inch reinforcing bars embedded in the
foundation and penetrating the bales by at least 12 inches, located
along the center line of the bale wall, spaced not more than two feet
apart. Other methods as determined by the engineer or architect may
also be used.
   (2) Nonbale walls abutting bale walls shall be attached by means
of one or more of the following methods or by means of an acceptable
equivalent:
   (A) Wooden dowels of 5/8 inch minimum diameter and of sufficient
length to provide 12 inches of penetration into the bale, driven
through holes bored in the abutting wall stud, and spaced to provide
one dowel connection per bale.
   (B) Pointed wooden stakes, a minimum of 12 inches in length and 1
1/2 inches by 3 1/2 inches at the exposed end, fully driven into each
course of bales, as anchorage points.
   (C) Bolted or threaded rod connection of the abutting wall,
through the bale wall, to a steel nut and steel or plywood plate
washer, a minimum of 6 inches square and a minimum thickness of 3/16
of an inch for steel and 1/2 inch for plywood, in a minimum of three
locations.
   (3) (A) Bale walls and roof bearing assemblies shall be anchored
to the foundation where necessary, as determined by the civil
engineer or architect, by means of methods that are adequate to
resist uplift forces resulting from the design wind load. There shall
be a minimum of two points of anchorage per wall, spaced not more
than 6 feet apart, with one located within 36 inches of each end of
each wall.
   (B) With loadbearing bale walls, the dead load of the roof and
ceiling systems will produce vertical compression of the walls.
Regardless of the anchoring system used to attach the roof bearing
assembly to the foundation, prior to installation of wall finish
materials, the nuts, straps, or cables shall be retightened to
compensate for this compression.
   (h) (1) A moisture barrier shall be used between the top of the
foundation and the bottom of the bale wall to prevent moisture from
migrating through the foundation so as to come into contact with the
bottom course of bales. This barrier shall consist of one of the
following:
   (A) Cementitious waterproof coating.
   (B) Type 30 asphalt felt over an asphalt emulsion.
   (C) Sheet metal flashing, sealed at joints.
   (D) Another building moisture barrier, as approved by the building
official.
   (2) All penetrations through the moisture barrier, as well as all
joints in the barrier, shall be sealed with asphalt, caulking, or an
approved sealant.
   (3) There shall also be a drainage plane between the straw and the
top of the foundation, such as a one inch layer of pea gravel.
   (i) (1) For nonloadbearing walls, bales may be laid either flat or
on edge. Bales in loadbearing bale walls shall be laid flat and be
stacked in a running bond, where possible, with each bale overlapping
the two bales beneath it. Overlaps shall be a minimum of 12 inches.
Gaps between the ends of bales which are less than 6 inches in width
may be filled by an untied flake inserted snugly into the gap.
   (2) Bale wall assemblies shall be held securely together by rebar
pins driven through bale centers as described in this chapter, or
equivalent methods as approved by the civil engineer or architect.
   (3) The first course of bales shall be laid by impaling the bales
on the rebar verticals and threaded rods, if any, extending from the
foundation. When the fourth course has been laid, vertical #4 rebar
pins, or an acceptable equivalent long enough to extend through all
four courses, shall be driven down through the bales, two in each
bale, located so that they do not pass through the space between the
ends of any two bales. The layout of these rebar pins shall
approximate the layout of the rebar pins extending from the
foundation. As each subsequent course is laid, two pins, long enough
to extend through that course and the three courses immediately below
it, shall be driven down through each bale. This pinning method
shall be continued to the top of the wall. In walls seven or eight
courses high, pinning at the fifth course may be eliminated.
   (4) Alternative pinning method to the method described in
paragraph (3): when the third course has been laid, vertical #4 rebar
pins, or an acceptable equivalent, long enough to extend through all
three courses, shall be driven down through the bales, two in each
bale, located so that they do not pass through the space between the
ends of any two bales. The layout of these rebar pins shall
approximate the layout of the rebar pins extending from the
foundation. As each subsequent course is laid, two pins, long enough
to extend through that course and the two courses immediately below
it, shall be driven down through each bale. This pinning method shall
be continued to the top of the wall.
   (5) Only full-length bales shall be used at corners of loadbearing
bale walls.
   (6) Vertical #4 rebar pins, or an acceptable alternative, shall be
located within one foot of all corners or door openings.
   (7) Staples, made of #3 or larger rebar formed into a "U" shape, a
minimum of 18 inches long with two 6-inch legs, shall be used at all
corners of every course, driven with one leg into the top of each
abutting corner bale.
   (j) (1) All loadbearing bale walls shall have a roof bearing
assembly at the top of the walls to bear the roof load and to provide
the means of connecting the roof structure to the foundation. The
roof bearing assembly shall be continuous along the tops of
loadbearing bale walls.
   (2) An acceptable roof bearing assembly option shall consist of
two double 2-inch by 6-inch, or larger, horizontal top plates, one
located at the inner edge of the wall and the other at the outer
edge. Connecting the two doubled top plates, and located horizontally
and perpendicular to the length of the wall, shall be 2-inch by
6-inch cross members, spaced no more than 72 inches center to center,
and as required to align with the threaded rods extending from the
anchor bolts in the foundation. The double 2-inch by 6-inch top
plates shall be face-nailed with 16d nails staggered at 16-inch o.c.,
with laps and intersections face-nailed with four 16d nails. The
crossmembers shall be face-nailed to the top plates with four 16d
nails at each end. Corner connections shall include overlaps nailed
as above or an acceptable equivalent, such as plywood gussets or
metal plates. Alternatives to this roof bearing assembly option shall
provide equal or greater vertical rigidity and provide horizontal
rigidity equivalent to a continuous double 2 by 4 top plate.
   (3) The connection of roof framing members to the roof plate shall
comply with the appropriate sections of the California Building
Standards Code.
   (k) All openings in loadbearing bale walls shall be a minimum of
one full bale length from any outside corner, unless exceptions are
approved by an engineer or architect licensed by the state to
practice. Wall or roof load present above any opening shall be
carried, or transferred, to the bales below by one of the following:
   (1) A frame, such as a structural window or door frame.
   (2) A lintel, such as an angle-iron cradle, wooden beam, or wooden
box beam. Lintels shall be at least twice as long as the opening is
wide and extend a minimum of 24 inches beyond either side of the
opening. Lintels shall be centered over openings.
   (3) A roof bearing assembly designed to act as a rigid beam over
the opening.
   ( l) (1) All weather-exposed bale walls shall be protected from
water damage. No vapor impermeable barrier may be used on bale walls,
and the civil engineer or architect may design the bale walls
without any membrane barriers between straw and plaster, except as
specified in this section, in order to allow natural transpiration of
moisture from the bales and to secure a structural bond between
plaster and straw.
   (2) Bale walls shall have special moisture protection provided at
all horizontal surfaces exposed to the weather. This moisture
protection shall be installed in a manner that will prevent water
from entering the wall system.
   (m) (1) Interior and exterior surfaces of bale walls shall be
protected from mechanical damage, flame, animals, and prolonged
exposure to water. Bale walls adjacent to bath and shower enclosures
shall be protected by a moisture barrier.
   (2) Cement stucco shall be reinforced with galvanized woven wire
stucco netting or an equivalent, as approved by the building
official. The reinforcement shall be secured by attachment through
the wall at a maximum spacing of 24 inches horizontally and 16 inches
vertically, unless substantiated otherwise by a civil engineer or
architect.
   (3) Where bales abut other materials, the plaster or stucco shall
be reinforced with galvanized expanded metal lath, or an acceptable
equivalent, extending a minimum of 6 inches onto the bales.
   (4) Earthen and lime-based plasters may be applied directly onto
bale walls without reinforcement, except where applied over materials
other than straw.
   (n) (1) All wiring within or on bale walls shall meet all
provisions of the California Electrical Code. Type "NM" or "UF" cable
may be used, or wiring may be run in metallic or nonmetallic conduit
systems.
   (2) Electrical boxes shall be securely attached to wooden stakes
driven a minimum of 12 inches into the bales, or an acceptable
equivalent.
   (o) Water or gas pipes within bale walls shall be encased in a
continuous pipe sleeve to prevent leakage within the wall. Where
pipes are mounted on bale walls, they shall be isolated from the
bales by a moisture barrier.
   (p) Bales shall be protected from rain and other moisture
infiltration at all times until protected by the roof of the
structure.



18944.41.  Sections 18944.30, 18944.31, 18944.33, 18944.35, and
18944.40 shall become inoperative when building standards become
effective after approval by the California Building Standards
Commission pursuant to Chapter 4 (commencing with Section 18935) that
permit the construction of structures that use baled straw as a
loadbearing or nonloadbearing material and that are safe to the
public.

State Codes and Statutes

Statutes > California > Hsc > 18944.40-18944.41

HEALTH AND SAFETY CODE
SECTION 18944.40-18944.41



18944.40.  (a) Straw-bale walls, when covered with plaster, drywall,
or stucco, shall be deemed to have the equivalent fire resistive
rating as wood-frame construction with the same wall-finishing
system.
   (b) Minimum bale wall thickness shall be 13 inches.
   (c) Buildings with loadbearing bale walls shall not exceed one
story in height without substantiating calculations and design by a
civil engineer or architect licensed by the state, and the bale
portion of the loadbearing walls shall not exceed a height-to-width
ratio of 5.6:1 (for example, the maximum height for a wall that is 23
inches thick would be 10 feet 8 inches).
   (d) The ratio of unsupported wall length to thickness, for
loadbearing walls, shall not exceed 15.7:1 (for example, for a wall
that is 23 inches thick, the maximum unsupported length allowed is 30
feet).
   (e) The allowable vertical load (live and dead load) on top of
loadbearing bale walls plastered with cement or lime cement plaster
on both sides shall not exceed 800 pounds per linear foot, and the
resultant load shall act at the center of the wall. Straw-bale
structures shall be designed to withstand all vertical and horizontal
loads, and the resulting overturning and base shear, as specified in
the latest edition of the California Building Standards Code.
Straw-bale walls plastered with cement or lime cement plaster on both
sides shall be capable of resisting in-plane lateral forces from
wind or earthquake of 360 pounds per linear foot.
   (f) Foundations shall be designed in accordance with the
California Building Standards Code to accommodate the load created by
the bale wall plus superimposed live and dead loads. Supports for
bale walls shall extend to an elevation of at least six inches above
adjacent ground at all points, and at least one inch above floor
surfaces.
   (g) (1) Bale walls shall be anchored to supports to resist lateral
forces, as approved by the civil engineer or architect. This may be
accomplished with one-half inch reinforcing bars embedded in the
foundation and penetrating the bales by at least 12 inches, located
along the center line of the bale wall, spaced not more than two feet
apart. Other methods as determined by the engineer or architect may
also be used.
   (2) Nonbale walls abutting bale walls shall be attached by means
of one or more of the following methods or by means of an acceptable
equivalent:
   (A) Wooden dowels of 5/8 inch minimum diameter and of sufficient
length to provide 12 inches of penetration into the bale, driven
through holes bored in the abutting wall stud, and spaced to provide
one dowel connection per bale.
   (B) Pointed wooden stakes, a minimum of 12 inches in length and 1
1/2 inches by 3 1/2 inches at the exposed end, fully driven into each
course of bales, as anchorage points.
   (C) Bolted or threaded rod connection of the abutting wall,
through the bale wall, to a steel nut and steel or plywood plate
washer, a minimum of 6 inches square and a minimum thickness of 3/16
of an inch for steel and 1/2 inch for plywood, in a minimum of three
locations.
   (3) (A) Bale walls and roof bearing assemblies shall be anchored
to the foundation where necessary, as determined by the civil
engineer or architect, by means of methods that are adequate to
resist uplift forces resulting from the design wind load. There shall
be a minimum of two points of anchorage per wall, spaced not more
than 6 feet apart, with one located within 36 inches of each end of
each wall.
   (B) With loadbearing bale walls, the dead load of the roof and
ceiling systems will produce vertical compression of the walls.
Regardless of the anchoring system used to attach the roof bearing
assembly to the foundation, prior to installation of wall finish
materials, the nuts, straps, or cables shall be retightened to
compensate for this compression.
   (h) (1) A moisture barrier shall be used between the top of the
foundation and the bottom of the bale wall to prevent moisture from
migrating through the foundation so as to come into contact with the
bottom course of bales. This barrier shall consist of one of the
following:
   (A) Cementitious waterproof coating.
   (B) Type 30 asphalt felt over an asphalt emulsion.
   (C) Sheet metal flashing, sealed at joints.
   (D) Another building moisture barrier, as approved by the building
official.
   (2) All penetrations through the moisture barrier, as well as all
joints in the barrier, shall be sealed with asphalt, caulking, or an
approved sealant.
   (3) There shall also be a drainage plane between the straw and the
top of the foundation, such as a one inch layer of pea gravel.
   (i) (1) For nonloadbearing walls, bales may be laid either flat or
on edge. Bales in loadbearing bale walls shall be laid flat and be
stacked in a running bond, where possible, with each bale overlapping
the two bales beneath it. Overlaps shall be a minimum of 12 inches.
Gaps between the ends of bales which are less than 6 inches in width
may be filled by an untied flake inserted snugly into the gap.
   (2) Bale wall assemblies shall be held securely together by rebar
pins driven through bale centers as described in this chapter, or
equivalent methods as approved by the civil engineer or architect.
   (3) The first course of bales shall be laid by impaling the bales
on the rebar verticals and threaded rods, if any, extending from the
foundation. When the fourth course has been laid, vertical #4 rebar
pins, or an acceptable equivalent long enough to extend through all
four courses, shall be driven down through the bales, two in each
bale, located so that they do not pass through the space between the
ends of any two bales. The layout of these rebar pins shall
approximate the layout of the rebar pins extending from the
foundation. As each subsequent course is laid, two pins, long enough
to extend through that course and the three courses immediately below
it, shall be driven down through each bale. This pinning method
shall be continued to the top of the wall. In walls seven or eight
courses high, pinning at the fifth course may be eliminated.
   (4) Alternative pinning method to the method described in
paragraph (3): when the third course has been laid, vertical #4 rebar
pins, or an acceptable equivalent, long enough to extend through all
three courses, shall be driven down through the bales, two in each
bale, located so that they do not pass through the space between the
ends of any two bales. The layout of these rebar pins shall
approximate the layout of the rebar pins extending from the
foundation. As each subsequent course is laid, two pins, long enough
to extend through that course and the two courses immediately below
it, shall be driven down through each bale. This pinning method shall
be continued to the top of the wall.
   (5) Only full-length bales shall be used at corners of loadbearing
bale walls.
   (6) Vertical #4 rebar pins, or an acceptable alternative, shall be
located within one foot of all corners or door openings.
   (7) Staples, made of #3 or larger rebar formed into a "U" shape, a
minimum of 18 inches long with two 6-inch legs, shall be used at all
corners of every course, driven with one leg into the top of each
abutting corner bale.
   (j) (1) All loadbearing bale walls shall have a roof bearing
assembly at the top of the walls to bear the roof load and to provide
the means of connecting the roof structure to the foundation. The
roof bearing assembly shall be continuous along the tops of
loadbearing bale walls.
   (2) An acceptable roof bearing assembly option shall consist of
two double 2-inch by 6-inch, or larger, horizontal top plates, one
located at the inner edge of the wall and the other at the outer
edge. Connecting the two doubled top plates, and located horizontally
and perpendicular to the length of the wall, shall be 2-inch by
6-inch cross members, spaced no more than 72 inches center to center,
and as required to align with the threaded rods extending from the
anchor bolts in the foundation. The double 2-inch by 6-inch top
plates shall be face-nailed with 16d nails staggered at 16-inch o.c.,
with laps and intersections face-nailed with four 16d nails. The
crossmembers shall be face-nailed to the top plates with four 16d
nails at each end. Corner connections shall include overlaps nailed
as above or an acceptable equivalent, such as plywood gussets or
metal plates. Alternatives to this roof bearing assembly option shall
provide equal or greater vertical rigidity and provide horizontal
rigidity equivalent to a continuous double 2 by 4 top plate.
   (3) The connection of roof framing members to the roof plate shall
comply with the appropriate sections of the California Building
Standards Code.
   (k) All openings in loadbearing bale walls shall be a minimum of
one full bale length from any outside corner, unless exceptions are
approved by an engineer or architect licensed by the state to
practice. Wall or roof load present above any opening shall be
carried, or transferred, to the bales below by one of the following:
   (1) A frame, such as a structural window or door frame.
   (2) A lintel, such as an angle-iron cradle, wooden beam, or wooden
box beam. Lintels shall be at least twice as long as the opening is
wide and extend a minimum of 24 inches beyond either side of the
opening. Lintels shall be centered over openings.
   (3) A roof bearing assembly designed to act as a rigid beam over
the opening.
   ( l) (1) All weather-exposed bale walls shall be protected from
water damage. No vapor impermeable barrier may be used on bale walls,
and the civil engineer or architect may design the bale walls
without any membrane barriers between straw and plaster, except as
specified in this section, in order to allow natural transpiration of
moisture from the bales and to secure a structural bond between
plaster and straw.
   (2) Bale walls shall have special moisture protection provided at
all horizontal surfaces exposed to the weather. This moisture
protection shall be installed in a manner that will prevent water
from entering the wall system.
   (m) (1) Interior and exterior surfaces of bale walls shall be
protected from mechanical damage, flame, animals, and prolonged
exposure to water. Bale walls adjacent to bath and shower enclosures
shall be protected by a moisture barrier.
   (2) Cement stucco shall be reinforced with galvanized woven wire
stucco netting or an equivalent, as approved by the building
official. The reinforcement shall be secured by attachment through
the wall at a maximum spacing of 24 inches horizontally and 16 inches
vertically, unless substantiated otherwise by a civil engineer or
architect.
   (3) Where bales abut other materials, the plaster or stucco shall
be reinforced with galvanized expanded metal lath, or an acceptable
equivalent, extending a minimum of 6 inches onto the bales.
   (4) Earthen and lime-based plasters may be applied directly onto
bale walls without reinforcement, except where applied over materials
other than straw.
   (n) (1) All wiring within or on bale walls shall meet all
provisions of the California Electrical Code. Type "NM" or "UF" cable
may be used, or wiring may be run in metallic or nonmetallic conduit
systems.
   (2) Electrical boxes shall be securely attached to wooden stakes
driven a minimum of 12 inches into the bales, or an acceptable
equivalent.
   (o) Water or gas pipes within bale walls shall be encased in a
continuous pipe sleeve to prevent leakage within the wall. Where
pipes are mounted on bale walls, they shall be isolated from the
bales by a moisture barrier.
   (p) Bales shall be protected from rain and other moisture
infiltration at all times until protected by the roof of the
structure.



18944.41.  Sections 18944.30, 18944.31, 18944.33, 18944.35, and
18944.40 shall become inoperative when building standards become
effective after approval by the California Building Standards
Commission pursuant to Chapter 4 (commencing with Section 18935) that
permit the construction of structures that use baled straw as a
loadbearing or nonloadbearing material and that are safe to the
public.


State Codes and Statutes

State Codes and Statutes

Statutes > California > Hsc > 18944.40-18944.41

HEALTH AND SAFETY CODE
SECTION 18944.40-18944.41



18944.40.  (a) Straw-bale walls, when covered with plaster, drywall,
or stucco, shall be deemed to have the equivalent fire resistive
rating as wood-frame construction with the same wall-finishing
system.
   (b) Minimum bale wall thickness shall be 13 inches.
   (c) Buildings with loadbearing bale walls shall not exceed one
story in height without substantiating calculations and design by a
civil engineer or architect licensed by the state, and the bale
portion of the loadbearing walls shall not exceed a height-to-width
ratio of 5.6:1 (for example, the maximum height for a wall that is 23
inches thick would be 10 feet 8 inches).
   (d) The ratio of unsupported wall length to thickness, for
loadbearing walls, shall not exceed 15.7:1 (for example, for a wall
that is 23 inches thick, the maximum unsupported length allowed is 30
feet).
   (e) The allowable vertical load (live and dead load) on top of
loadbearing bale walls plastered with cement or lime cement plaster
on both sides shall not exceed 800 pounds per linear foot, and the
resultant load shall act at the center of the wall. Straw-bale
structures shall be designed to withstand all vertical and horizontal
loads, and the resulting overturning and base shear, as specified in
the latest edition of the California Building Standards Code.
Straw-bale walls plastered with cement or lime cement plaster on both
sides shall be capable of resisting in-plane lateral forces from
wind or earthquake of 360 pounds per linear foot.
   (f) Foundations shall be designed in accordance with the
California Building Standards Code to accommodate the load created by
the bale wall plus superimposed live and dead loads. Supports for
bale walls shall extend to an elevation of at least six inches above
adjacent ground at all points, and at least one inch above floor
surfaces.
   (g) (1) Bale walls shall be anchored to supports to resist lateral
forces, as approved by the civil engineer or architect. This may be
accomplished with one-half inch reinforcing bars embedded in the
foundation and penetrating the bales by at least 12 inches, located
along the center line of the bale wall, spaced not more than two feet
apart. Other methods as determined by the engineer or architect may
also be used.
   (2) Nonbale walls abutting bale walls shall be attached by means
of one or more of the following methods or by means of an acceptable
equivalent:
   (A) Wooden dowels of 5/8 inch minimum diameter and of sufficient
length to provide 12 inches of penetration into the bale, driven
through holes bored in the abutting wall stud, and spaced to provide
one dowel connection per bale.
   (B) Pointed wooden stakes, a minimum of 12 inches in length and 1
1/2 inches by 3 1/2 inches at the exposed end, fully driven into each
course of bales, as anchorage points.
   (C) Bolted or threaded rod connection of the abutting wall,
through the bale wall, to a steel nut and steel or plywood plate
washer, a minimum of 6 inches square and a minimum thickness of 3/16
of an inch for steel and 1/2 inch for plywood, in a minimum of three
locations.
   (3) (A) Bale walls and roof bearing assemblies shall be anchored
to the foundation where necessary, as determined by the civil
engineer or architect, by means of methods that are adequate to
resist uplift forces resulting from the design wind load. There shall
be a minimum of two points of anchorage per wall, spaced not more
than 6 feet apart, with one located within 36 inches of each end of
each wall.
   (B) With loadbearing bale walls, the dead load of the roof and
ceiling systems will produce vertical compression of the walls.
Regardless of the anchoring system used to attach the roof bearing
assembly to the foundation, prior to installation of wall finish
materials, the nuts, straps, or cables shall be retightened to
compensate for this compression.
   (h) (1) A moisture barrier shall be used between the top of the
foundation and the bottom of the bale wall to prevent moisture from
migrating through the foundation so as to come into contact with the
bottom course of bales. This barrier shall consist of one of the
following:
   (A) Cementitious waterproof coating.
   (B) Type 30 asphalt felt over an asphalt emulsion.
   (C) Sheet metal flashing, sealed at joints.
   (D) Another building moisture barrier, as approved by the building
official.
   (2) All penetrations through the moisture barrier, as well as all
joints in the barrier, shall be sealed with asphalt, caulking, or an
approved sealant.
   (3) There shall also be a drainage plane between the straw and the
top of the foundation, such as a one inch layer of pea gravel.
   (i) (1) For nonloadbearing walls, bales may be laid either flat or
on edge. Bales in loadbearing bale walls shall be laid flat and be
stacked in a running bond, where possible, with each bale overlapping
the two bales beneath it. Overlaps shall be a minimum of 12 inches.
Gaps between the ends of bales which are less than 6 inches in width
may be filled by an untied flake inserted snugly into the gap.
   (2) Bale wall assemblies shall be held securely together by rebar
pins driven through bale centers as described in this chapter, or
equivalent methods as approved by the civil engineer or architect.
   (3) The first course of bales shall be laid by impaling the bales
on the rebar verticals and threaded rods, if any, extending from the
foundation. When the fourth course has been laid, vertical #4 rebar
pins, or an acceptable equivalent long enough to extend through all
four courses, shall be driven down through the bales, two in each
bale, located so that they do not pass through the space between the
ends of any two bales. The layout of these rebar pins shall
approximate the layout of the rebar pins extending from the
foundation. As each subsequent course is laid, two pins, long enough
to extend through that course and the three courses immediately below
it, shall be driven down through each bale. This pinning method
shall be continued to the top of the wall. In walls seven or eight
courses high, pinning at the fifth course may be eliminated.
   (4) Alternative pinning method to the method described in
paragraph (3): when the third course has been laid, vertical #4 rebar
pins, or an acceptable equivalent, long enough to extend through all
three courses, shall be driven down through the bales, two in each
bale, located so that they do not pass through the space between the
ends of any two bales. The layout of these rebar pins shall
approximate the layout of the rebar pins extending from the
foundation. As each subsequent course is laid, two pins, long enough
to extend through that course and the two courses immediately below
it, shall be driven down through each bale. This pinning method shall
be continued to the top of the wall.
   (5) Only full-length bales shall be used at corners of loadbearing
bale walls.
   (6) Vertical #4 rebar pins, or an acceptable alternative, shall be
located within one foot of all corners or door openings.
   (7) Staples, made of #3 or larger rebar formed into a "U" shape, a
minimum of 18 inches long with two 6-inch legs, shall be used at all
corners of every course, driven with one leg into the top of each
abutting corner bale.
   (j) (1) All loadbearing bale walls shall have a roof bearing
assembly at the top of the walls to bear the roof load and to provide
the means of connecting the roof structure to the foundation. The
roof bearing assembly shall be continuous along the tops of
loadbearing bale walls.
   (2) An acceptable roof bearing assembly option shall consist of
two double 2-inch by 6-inch, or larger, horizontal top plates, one
located at the inner edge of the wall and the other at the outer
edge. Connecting the two doubled top plates, and located horizontally
and perpendicular to the length of the wall, shall be 2-inch by
6-inch cross members, spaced no more than 72 inches center to center,
and as required to align with the threaded rods extending from the
anchor bolts in the foundation. The double 2-inch by 6-inch top
plates shall be face-nailed with 16d nails staggered at 16-inch o.c.,
with laps and intersections face-nailed with four 16d nails. The
crossmembers shall be face-nailed to the top plates with four 16d
nails at each end. Corner connections shall include overlaps nailed
as above or an acceptable equivalent, such as plywood gussets or
metal plates. Alternatives to this roof bearing assembly option shall
provide equal or greater vertical rigidity and provide horizontal
rigidity equivalent to a continuous double 2 by 4 top plate.
   (3) The connection of roof framing members to the roof plate shall
comply with the appropriate sections of the California Building
Standards Code.
   (k) All openings in loadbearing bale walls shall be a minimum of
one full bale length from any outside corner, unless exceptions are
approved by an engineer or architect licensed by the state to
practice. Wall or roof load present above any opening shall be
carried, or transferred, to the bales below by one of the following:
   (1) A frame, such as a structural window or door frame.
   (2) A lintel, such as an angle-iron cradle, wooden beam, or wooden
box beam. Lintels shall be at least twice as long as the opening is
wide and extend a minimum of 24 inches beyond either side of the
opening. Lintels shall be centered over openings.
   (3) A roof bearing assembly designed to act as a rigid beam over
the opening.
   ( l) (1) All weather-exposed bale walls shall be protected from
water damage. No vapor impermeable barrier may be used on bale walls,
and the civil engineer or architect may design the bale walls
without any membrane barriers between straw and plaster, except as
specified in this section, in order to allow natural transpiration of
moisture from the bales and to secure a structural bond between
plaster and straw.
   (2) Bale walls shall have special moisture protection provided at
all horizontal surfaces exposed to the weather. This moisture
protection shall be installed in a manner that will prevent water
from entering the wall system.
   (m) (1) Interior and exterior surfaces of bale walls shall be
protected from mechanical damage, flame, animals, and prolonged
exposure to water. Bale walls adjacent to bath and shower enclosures
shall be protected by a moisture barrier.
   (2) Cement stucco shall be reinforced with galvanized woven wire
stucco netting or an equivalent, as approved by the building
official. The reinforcement shall be secured by attachment through
the wall at a maximum spacing of 24 inches horizontally and 16 inches
vertically, unless substantiated otherwise by a civil engineer or
architect.
   (3) Where bales abut other materials, the plaster or stucco shall
be reinforced with galvanized expanded metal lath, or an acceptable
equivalent, extending a minimum of 6 inches onto the bales.
   (4) Earthen and lime-based plasters may be applied directly onto
bale walls without reinforcement, except where applied over materials
other than straw.
   (n) (1) All wiring within or on bale walls shall meet all
provisions of the California Electrical Code. Type "NM" or "UF" cable
may be used, or wiring may be run in metallic or nonmetallic conduit
systems.
   (2) Electrical boxes shall be securely attached to wooden stakes
driven a minimum of 12 inches into the bales, or an acceptable
equivalent.
   (o) Water or gas pipes within bale walls shall be encased in a
continuous pipe sleeve to prevent leakage within the wall. Where
pipes are mounted on bale walls, they shall be isolated from the
bales by a moisture barrier.
   (p) Bales shall be protected from rain and other moisture
infiltration at all times until protected by the roof of the
structure.



18944.41.  Sections 18944.30, 18944.31, 18944.33, 18944.35, and
18944.40 shall become inoperative when building standards become
effective after approval by the California Building Standards
Commission pursuant to Chapter 4 (commencing with Section 18935) that
permit the construction of structures that use baled straw as a
loadbearing or nonloadbearing material and that are safe to the
public.